Piston construction



Feb. 25, 1947. L, E, LEUPE 2,416,487

PISTON CONSTRUCTION Filed July 14, 1945 we E.' EUPE AT' TURNE Y Patented Feb. 25, 1947 UNITED STATES PATENT OFFICE vki PISTON CONSTRUCTION y Louis E. Leupe, Burlingame, Calif. Application July 14, 1945, Serial No. 605,148`

2 claims.

This invention relates to an improved piston l'or use in internal combusion engines and has particular reference to an improved form of construction for enabling thev piston wall to resiliently yield inwardly when the outer diameter of the piston expands to a greater size than the inner diameterrof the cylinder due to the extreme heat developed in the operation of the engine and to the methods employed for externally cooling the cylinders. vIt is desirable to have the skirt portion of the piston snugly fit in the cylinder in order to produce a seal that will assist the piston rings in preventing leakage of gas past the piston. In the operation of the engine the pistons are subjected to a higher heat temperature than the cylinders due to the provision of means for cooling the walls of 'the cylinders and this difference in extreme heat temperature causes the pistons to expand to a greater degree than the cylinders, resulting in binding and excessive friction during the reciprocative movement of the pistons in the cylinders.

It is therefore an object of the present 'invention to provide an improved form of construction for pistons used in internal combustion engines, Diesel engines and the like, whereby the piston walls will be capable of resiliently yielding to make up for the greater expansion' of the pistons with respect to the cylinders and will enable the pistons to operate with the greatest eiciency during the normal operation of the engine.

Another object of the present invention is to form a pair of oppositely opposed longitudinal slots through the circular periphery of the piston wall. forming the skirt portion and to continue said piston wall inwardly around said slots, producing a pair of oppositely opposed inwardly extending channel formations that extend from the bottom of the skirt portion to the head portion and to further provide a transverse slot adjacent the head portion, said slot connecting With the groove of the channel formations thus providing a piston with a segmented wall that is completely free to evenly expand and contract from end to end andthus producing a piston that will form the proper seal, will not bind 4and Will operate with the maximum eiiciency.l

Other objects and advantages will be apparent during the course of the following description.

In the accompanying drawings forming a part of the specification and in which like numerals are employed to designate like parts throughout the same;

Fig. 1 is a vertical side elevational view of the piston, looking directly into one of the elongated channelv formations and showing the cross slot that extends through a portion of the peripherial wall of the piston and into the groove of the channel formation;

Fig. 2 is a vertical side elevational view of the piston showing both of the oppositely opposed channel formations and the cross slot that extends from one to the other;

Fig. 3 is a bottom plan View of the improved Y piston and particularly illustrates the oppositely opposed channel formations and the manner in which the periphery of the piston wall extends inwardly to form the same;

Fig. 4 is a sectional plan view taken on line 4-4 of Fig. 2, looking in direction of the arrows;

Fig. 5 is a longitudinal sectional view taken on line 5 5 of Fig. 3.

Referring in detail to the drawings and to the numerals thereof, the numeral 1 designates the main body portion of the piston, commonly called the skirt, and the numerals 8 and 9, the head portion and bottom respectively. The numeral l0 designates a series of circumferential grooves for holding conventional piston rings not shown.l The head portion 8 of the piston has a. slightly smaller diameter than the skirt 1, as shown by the dotted circle in Fig. 3, in order to allow for heat expansion, as this part of the piston which carries the piston rings is formed into a greater thickness of metal as indicated at I0 in Fig. 5 and is not yielding. The body y portion 'l of the piston must have a snug -t with the cylinder in order to reduce gas leakage and must therefore be resiliently contractable in order to allow for heat expansion.

The improved means provided for enabling the skirt of the piston to be resilientlyV contractable consists in forming a `pair of oppositely opposed elongated slots l2 and I4 through the periphery of the cylindrical wall l and extending the metal Yfrom said wall inwardly and around said slots, providing a pair of oppositely opposed elongated channel formations I5 and i6 that are integral with the cylindrical wall 1 as shown in Fig. 3 and longitudinally extending from the bottom 9 of the piston to a cross slot I1 that cuts through the wall 'l of the piston and transversely runs from one channel .formation to the other, as shown in Figs. 1 and 2 and 4. It will be noted that a segmental wall 1' is thus formed between the channel formations and the cross slot and ls completely free to resiliently contract in an even manner, thus enabling the piston to be reciprocative in the cylinders with the maximum of efciency during the normal operation of the engine.

A pair of bosses I8 and I9 are formed Within the piston, each boss having a hole 20 and 2|, respectively, forming Asuitable Wrist pin bearings. The improved piston is preferably made light in weight and is cam ground and the skirt portion is formed as thin as possible to give the proper resiliency andis constructed out of anysuitable metal that Will best serve the purpose of the invention.

It is to be understood that the form of the invention herewith shown and describedlis'sto he,vw taken asY a preferred example of thesame and" that Various changes relative to the material,

4 head portion and a skirt portion formed, from a single piece of material, the head portion having a smaller outer and inner diameter than the skirt portion, a, series of circumferential grooves in the periphery of the head'portion for holding a series of piston rings, a, pair of oppositely opposed bosses provided Within the skirt and having openings therein capable of forming wrist pin bearings, a pair ofzoppos'itely opposed channel vformations invlardly extending 'from the outer periphery of the skirt portion and'long'itudnally extending in parallelism from the bottom thereof toward the head portion and in proximity theref t osaidchannel formations being positioned on size, shape and arrangement of parts,' m ay .be f

resorted to without departing from the ,spirit of,v

the invention or the,scope of the subjoined claims.

VHaving thus described my inventiomlclaim; 1.5A pistonY embodying :in its construction a head portionV and a skirt portion,A a pair of oppositely opposed channel formations inwardly extending fromthe outer peripheryl of the skirt portion and longitudinally extending from the bottom `thereof toward the head portion aifid in proximity thereto, and a transverse-slot provided through said periphery and Y'joining the channel ,formations adjacent the-head portion.V

2; Avpistonv embodying in'its construction a one side of said bosses, and a transverse slit provided-through said periphery and joining the insidevoffboth channel formations adjacent the head portion.

f LOUIS E. LEUPE.

REFERENCES .CITED The following references are file or this patent: f

UNITEDl STATES PATENTS of record Vin the 

